Fuel properties, engine performance and environmental benefits of biodiesel produced by a green process

Biodiesel, produced by enzymatic transesterification of cottonseed oil with methanol in a green, zero waste discharge process, was purified to meet the international specifications. Glycerol was recovered by gravity separation and unutilized methanol was recycled after distillation. The methyl ester content of the purified product was found to be almost 90%. The fuel properties of the product and its blends with petroleum diesel were in well accordance with the international standards. The performance characteristics of the diesel engine with the blends (B10 and B20) were comparable to that of diesel in terms of brake thermal efficiency (BTE), brake specific fuel consumption (BSFC) and exhaust gas temperature (EGT). The emission characteristics of the engine with the blends were such that significant environmental benefits could be accrued, as the average emissions of CO, CO2, smoke and un-burned hydrocarbons (HCs) got considerably reduced by 33.3%, 8.4%, 43.4% and 29.4% respectively. However, in case biodiesel, relatively higher levels of NOX emission can be attributed to the inherent oxygen of biodiesel. Thus, the B10 and B20 products based on biodiesel from the green process showed comparable engine performance with better green house gas emission characteristics and hence, deserve the status of an efficient environment friendly bio-additive for diesel engines.